package thread;

public class ThreadDemo21 {
    public static void main(String[] args) throws InterruptedException {
        Object locker = new Object();
        Thread t  = new Thread(()->{
            synchronized (locker){
                synchronized (locker){
                    // .. suibian
                    System.out.println("hello");
                }
            }
        });

        t.start();
        t.join();
    }
}
